In the event that it is believed that potentially hazardous chemicals are present in the ground, an important part of the remediation task is to determine the extent of the contamination. Preferably, a thorough mapping and subsurface analyses should be conducted to assess the hazards and the possible solutions. For example, cone penetrometer systems are known for performing subsurface analyses and are able to provide valuable information about the subsurface materials and conditions.
The cone penetrometer is typically a self-contained system carried by a truck which can be moved into an area and begin the process of acquiring data. The system basically comprises powerful hydraulic rams for driving an assembled rod string, having sensors at the tip and along the string, down into the earth at a controlled speed to a depth of 100 feet or more. Clearly, the nature of such environmental investigations inherently involves the likelihood of contaminating the rod string. Thus, when the rod string is withdrawn from the ground, the operator is likely to be exposed to the hazardous chemical while disassembling the string.
The current procedure for decontaminating the rod string is to spray hot water with a jet spray to wash off the contamination. However, this is not satisfactory since the hazardous materials are then deposited on the ground. Moreover, the jet spray tends to use a lot of water and be rather wasteful. Accordingly, the self-contained truck must reserve substantial space and weight carrying ability for the water and this is not a satisfactory arrangement.
U.S. Pat. No. 4,503,577 to Fowler describes a decontamination apparatus for removing radioactive particles from long cylindrical pipes. The pipes are pulled horizontally through a sealed housing and the radioactive particles are removed by liquid freon sprayed onto the peripheral surfaces of the pipes. The operation of the apparatus, however, requires substantial handling of the pipes by operating personnel. As such, the use of the apparatus includes costs for safety suits and exposure prevention gear as well as the increased risks of contaminating the operating personnel during handling. In addition, the apparatus is limited to decontaminating rods in substantially the horizontal plane since it is likely that liquid freon will leak through the seals if the apparatus were tilted at an angle.
Other arrangements are known for generally cleaning the exterior surfaces of pipes and rods. For example, U.S. Pat. No. 4,570,285 to Skelton discloses a device for removing rust and debris from wire ropes with wire brushes. The device even includes followers to guide the brushes into the recesses of the ropes. However, the device is not suitable for decontaminating the rope or any other generally cylindrical article. The brushes are more likely to spread the contamination around rather then remove it.
Similarly, U.S. Pat. No. 2,631,315 to Hauser discloses a pipe cleaning machine which is designed to remove heavy tar-like protective coatings or rust buildups from the exterior surfaces of pipes. However, simply scouring the surface with an abrasive does not render the pipe decontaminated.
There are a number of other devices, such as disclosed in U.S. Pat. Nos. 2,937,894 to Martin et al., 3,475,781, to Grant and 4,279,300 to Wirsch, relate to devices which encircle rods or pipes for spraying or treating the exterior surfaces thereof. However, these references are not pertinent to cleaning a contaminated pipe and are, therefore, not discussed in detail.
Accordingly, it is an object of the present invention to provide a method and apparatus which overcomes the drawbacks and disadvantages of the prior art as discussed above.
It is also an object of the present invention to provide a method and apparatus for decontaminating shafts of indeterminate length.
It is a more particular object to provide a method and apparatus for decontaminating shafts in an environmentally sound and responsible manner.
It is also an object of the present invention to clean and decontaminate rod strings as they are withdrawn from the ground prior to being handled by operating personnel.
It is a further object of the present invention to provide a method and apparatus for cleaning and decontaminating rod strings used in environmentally hazardous situations where the string is likely to become contaminated.